Leases - Components of Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 1,957	$ 2,027	$ 1,907
Finance lease cost:
Amortization of assets	92	79	78
Interest on lease liabilities	38	43	48
Variable lease cost	1,801	2,558	2,353
Total net lease cost	3,888	4,707	4,386
American Airlines, Inc.
Lessee, Lease, Description [Line Items]
Operating lease cost	1,943	2,012	1,889
Finance lease cost:
Amortization of assets	92	79	78
Interest on lease liabilities	38	43	48
Variable lease cost	1,786	2,542	2,353
Total net lease cost	$ 3,859	$ 4,676	$ 4,368